Local police stand on a track and watch as carriages are removed from the site of the accident

The death toll continues to climb from Monday's train derailment between Osaka and Kobe, in western Japan. Authorities say 73 people died and more than 440 were injured.

At the crash site, large cranes and other heavy equipment have been brought in to tear apart the mangled carriages - some embedded in the ground floor of the apartment building. Firefighters were still trying to reach some passengers believed trapped in the wreckage.

There was some good news early Tuesday. Two teenaged university students and a 46-year-old woman were pulled alive from one of the demolished train carriages. Doctors say they were fully conscious and responding to questions.

Meanwhile, police have opened a criminal investigation - going through files at West Japan Railway, the operator of the train that derailed and hit an apartment building during Monday morning rush hour.

Mr. Kitagawa says it is critical for investigators to determine just how fast the train was running when it derailed.

But even before the investigation is complete, the railway operator is signaling that it will take responsibility for the country's worst rail accident in more than 40 years. The company's three top executives are expected to step down, including Chairman Shojiro Nanya.

Mr. Nanya visited a makeshift morgue for the crash victims at a local gymnasium to express the railway's grief.

The railway chairman says top officials can not avoid accepting responsibility for the disaster, regardless of what the cause might be.

The train's driver, 23-year-old Ryujiro Takami, had less than a year on the job and two previous reprimands. Attention has focused on his handling of the train. Numerous passengers have told reporters and investigators they thought the train was traveling too fast to make up for being about two minutes behind schedule after overshooting a previous station and having to back up.

Japanese rail experts expressed doubt that the train could have reached a high enough speed for that to be the sole cause of the derailment. They believe the accident might have been caused by a number of factors, including speed, poor maintenance, aging rails and possibly, objects, on the tracks.

The railway says it has found evidence of stones on the tracks but it has no idea yet whether that could have contributed to the crash.